Screening Of The Flocculant-Producing Strain And Its Application In Oil-Polluted Wastewater Treatment

The thesis are focused mainly on the screening of the flocculant-producing strain and its application in oil-polluted wastewater treatment.Three screening methods are studied, which are conventional method, DEHP method, and pyridine method. The results of screening studies indicated that the pyridine method is far better than other two.With pyridine method, a flocculant-producing strain B-6-1 was isolated and identified belong to Enterobacter. B-6-1 could produce a strong activity flocculant, with flocculating rate of 92.5% against Kaolin clay suspension. To obtain high-yield strain, UV Mutation technology were applyed on B-6-1 protoplast. The mutants P33 and P30 were obtained by the primary and secondary screen, which increased their flocculanting rate from 92.5% to 98.5% and 97.6%, respectively.The optimum flocculant-producing conditions of P33 were studied by single factor. The optimal combinations were as follow: sucrose 20g, CO(NH2)2 0.75g, yeast 0.75g, KH2PO4 2g, K2HPO4 5g, NaCl 0.1g, water 1000mL, natural pH, culture at 28℃on a rotary shaker with a speed of 160 rpm for 20h.The flocculation effect of bioflocculantl and poly-Al on the treatment of oil-polluted water is compared. Pilot tests show the flocculation effect of bioflocculant is better than poly-Al. Compared with poly-Al, bioflocculant have better flocculating effect, higher speed, implying the broad application prospects of bioflocculants in practice.